Seminar

Abstract

The cooling of the stratosphere is an important fingerprint of CO2 on the climate system. This stratospheric signature of CO2, however, is confounded by the presence of ozone-depleting substances (ODS). The talk will summarize the latest observations and, with simple arguments and with the help of ensembles of chemistry-climate model integrations, demonstrate the crucial role of ODS not only on stratospheric temperature trends, but also on the entire large-scale circulation of the stratosphere. The impact of the Montreal Protocol on the detection of the vertical fingerprint of anthropogenic forcing of atmospheric temperatures will be also be discussed.

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Prof. Lorenzo Polvani's research encompasses many aspects of atmospheric and climate dynamics, including the physical response of the climate system to increasing concentrations of carbon dioxide, the chemistry and dynamics of the stratosphere, Arctic and Antarctic climate change, and past and future climate impacts caused of the Montreal Protocol. He is particularly interested in quantifying and distinguishing the effects of anthropogenic forcings from natural climate variability. He also retains an interest in geophysical fluid dynamics, and occasionally dabbles in planetary atmospheres.